Blast tube for oil burners



8- 0, 1949- A. E. WATTS 2,480,345

BLAST-TUBE FOR OIL BURNERS Filed June s, 1946 2 Sheets-Sheet 1 INVENTOR WM JMM ATTORNEY Aug. 30, 1949. A. E. mu

BLAST TUBE FOR OIL BURNERS Filed June 3, 19 46 2 Sheets-Sheet 2 INVENTOR wm 5M. m

ATTOR NEY Patented Aug. 30, 1949 UNITED STATES PATENT OFFICE BLAST TUBE FOR OIL BURNERS Albert Edward Watts, Montreal, Quebec, Canada Application June 3, 1946, Serial No. 674,149

3 Claims.

This invention relates to improvements in air cones for oil burners as described in the present specification and illustrated in the accompanying drawings, which form a part of the same.

The invention consists essentially of the novel features of construction as pointed out broadly and specifically in the claims for novelty following a description containing an explanation in detail of an acceptable form of the invention.

The objects of the invention are to provide a blast tube for oil burners which will generate the maximum of heat at the minimum of expense; to direct the flow of air and vaporized fuel in the blast tube so as to efficiently produce a hot flame; to devise a blast tube which in cooperation with a nozzle willefficiently atomize and vaporize the fuel, mixing it evenly with air, before it is discharged from the tube in the form of a concentrated flame; to provide a blast tube in which the fluid is ignited the instant the. oil burner is switched on or started avoiding any waste; to construct a blast tube which will burn all the fluid remaining therein, when thecoil burner is shut down; to devise a blast tube in which no vacuum is created when the fire starts, thus avoiding any throw-back or pulsating of flame; to provide a blast tube having vanes which rotate or whirl the gases creating a concentrated heat at the mouth of the conical refractory member; to construct a blast tube which produces a concentrated flame at the mouth of the conical refractory member, rather than within same, thus prolonging the life of same; to devise a blast tube in which the conical refractory member can be easily replaced or removed for cleaning; to construct a blast tube which will permit the ignition to be shut off after the flame has been started; and generally to provide a blast tube which will be durable and efficient for its purpose.

In the drawings:

Figure 1 is a diagrammatic side elevation of an oil burner showing the blast tube fitted on same, and being separated from the mechanism of the oil burner by fire brick and insulation.

Figure 2 is a side sectional View of the blast tube showing the oil nozzle and ignition assembled therein,

Figure 3 is a front view of the blast tube having the conical refractory member, 011 nozzle and ignition assembly omitted.

Figure 4 is an enlarged front view of the blast tube showing the oil nozzle and ignition assembled therein.

Figure 5 is a side sectional view of the conical r fractory-member. v

Figure 6 is a side sectional view showing a modification of the conical refractory member.

Like numerals of reference indicate corresponding parts in the various figures.

Referring to the drawings, the blast tube illustrated in Figure 1 is indicated by the numeral [0 and is shown assembled on the air and fuel supply means l l of the oil burner. This air and fuel supply means I l and its mechanism is separated from the fire box by the fire wall l2 and the insulation IZA.

The blast tube l0 consists of a tube l9 and an inner conical member I3 having the cup-shaped member i4 securely fitted on the end thereof. The outer surface of the inner conical member 53 being smaller at the forward portion of same and forming a shoulder to accommodate this cupshaped member M. The inner conical member l3 has the forward portion of the inner wall cylindrical in shape, while the rear portion of the inner wall is of a conical or truncated shape. The cup-shaped member l4 has the rear portion of the inner wall cylindrical in shape and coinciding approximately in size to that of the outer surface of the forward portion of the inner conical member l3. This rear portion of the inner wall of the cup-shaped member l4 having a shoulder towards the front thereof. The inner and outer surfaces of the forward portion of this cup-shaped member l4 being of a truncated shape. A series of holes l5 are provided in the wall of the cupshaped member l4 towards the front thereof. These holes permitting part of the air to pass through same, and to be thrust upon the side wall of the conical refractory member l1.

Vanes I6 form a part of the inner conical member I3 being located in the forward portion of same. These vanes function in co-operation with the forward truncated portion of the cup-shaped member M in directing the flow of air which passes through same. While these vanes l6 and the truncated portion of the cup-shaped member 14 are shown a definite shape, any similar method might be employed which would achieve the same results, without generally aifecting the advantages of the invention. The vanes [6 are shown extending inward in a longitudinally inclined plane from the inner wall of the inner conical member l3. These vanes have the rear portion rounded minimizing resistance to the fiow of air in the inner conical member l3. The vanes I6 then curve towards the front, each forming an are at a' predetermined angle, which alters the course of the flow of air in the blast tube into a rotating or whirling form as it leaves the front edge of the vanes. These vanes could be formed in any other suitable manner that would achieve the same results, without generally affecting the advantages of the invention.

The conical refractory member I! may be made of any suitable material having heat resisting qualities, and being of a predetermined shape and size. The rear portion of this conical refractory member I? has the inner walls cylindrical in shape and of a suitable size to fit tightly over the straight walled portion of the cup-shaped member i i. The rear portion of this conical refractory member 5'! having the inner walls bevelled along the edge to facilitate the assembly of same on the cup-shaped member I l and also to coincide with the portion of the inner conical member l3 over which the conical refractory member is fitted. The conical refractory member l'l extends forward and outward from the cylindrical portion of same a predetermined distance and then extends inward at a slight angle to form a cup-shaped portion at the end thereof. The angle at which the inner wall of this conical refractory member tapers outward and then inward may vary, as it may be shaped to conform with the other parts, of the blast tube. The shape of this conical refractory member is also a factor in determining the form or shape of flame desired at the mouth of same.

A modification of the conical refractory member I1 is shown in Figure 6 in which the refractory member i 3 extends forward and outward from the cylindrical portion of same a predetermined distance and at a suitable angle.

The rear portion of the inner conical member i3 is fitted in the tube I9 which is made of any suitable material and of a predetermined size. This tube if is securely mounted on the air and fuel supply means I I of the oil burner and accommodates the oil pipe line 26 and the ignition assembly 2i. The bracket 22 is fixedly secured to the inner wall of the tube is and provides a means of holding the oil pipe line and ignition assembly 2! firmly in position. The oil pipe line extends through this tube 49 and into the inner conical member 23 where a nozzle 23 is mounted on the end thereof. The ignition assembly also extends through this tube l9 having the ignition points 25 suitably located at the front end of the nozzle 23. The angle at which the fuel is sprayed from this nozzle 23 is a factor in determining the angle of the walls of the conical refractory member H.

The air and fuel supply means H of the oil burner supplies the necessary forced air, fuel and ignition. The fuel or oil is pumped through the pipe line 23 and into the nozzle 23. As the oil is sprayed through the end of this nozzle, the forced air passing through the tube i9 and into the inner conical member I3 is mixed with same forming a combustible vapor. This vapor is ignited by the ignition points 26 and the flame is directed or carried towards the mouth of the conical refractory member H by the force of air passing through the inner conical member !3. As the vapor, which is a mixture of oil and air, passes through the forward portion of the inner conical member l3 it is rotated or whirled around by the fins or vanes it. The whirling vapor then passes into the truncated portion of the cup" shaped member Hi, part of this whirling vapor passing through the holes l5 and the remainder passing through the open end of this cup-shaped member. The whirling vapor is then thrown against the inner wall of the conical refractory member I! and is allowed to increase the size of its diametrical form until it reaches the end portion of this refractory member. As the end portion of the conical refractory member I1 tapers inward the whirling vapor is compressed as it passes through same creating a concentrated flame at the mouth of the refractory member.

The holes It in the Wall of the cup-shaped member ldpermit a portion of the vapor to pass therethrough, following the inner wall of the conical refractory member I! towards the outer edge thereof. This force of vapor, thus holding the flame at the outer edge or mouth of the conical refractory member and burning the vapor as itcomes in contact with the oxygen. During the operation of the blast tube, the air passing along the sides of the cup prevents the formation of any vacuum and definitely eliminates pulsations in the flame.

In the modification of the conical refractory member, as shown in Figure 6, the whirling vapor passes through the cup-shaped member it in the same manner as previously described and is thrown against the inner wall of the refractory member l8 and assuring rapid combustion on the outer edges of the flame. The whirling vapor being allowed to increase the size of its diametrical form as it passes towards the mouth of this refractory member, where a large, but less concentrated flame is created.

The ignition system is used only for the purpose of igniting the oil and air mixture and is shut off after a few seconds.

The conical refractory members i! and it are constructed so as to fit snugly over the cup-shaped member id, and at the same time facilitate the removal or replacement of same.

The vanes and the outer cup being porcelain enameled or treated with any refractory material so as to assure a smooth flow of the air and high refractory conditions.

It will be seen from the foregoing that a blast tube for oil burners has been devised that will be durable, efficient, and increase the volume of heat obtainable from same.

What I claim is:

1. In blast tubes for oil burners, a tube, an inner conical member fitted in the forward portion of said tube, and a cup-shaped member fitted on the forward portion of said inner conical member and having a central aperture, the outer surface of said inner conical member being smaller at the forward portion thereof and forming a shoulder to accommodate said cup-shaped member, the inner wall of said inner conical member bein cylindrical at the forward portion of same and the remaining portion thereof tapering outward towards the rear, the inner wall of said cupshaped member being cylindrical at the rear of same and forming a shoulder towards the front thereof, which abuts. the front edge of said inner conical member, the inner and outer surfaces of the forward portion of said cup-shaped member being of a truncated shape and tapering forward and inward, the forward portion of said cupshaped member having .a' plurality of holes extending therethrough, a conical refractory member fitted over the rear portion of said cupshaped member and extending forward and outward therefrom over the forward portion of said cup-shaped member, the holes in said cup-shaped member providing outlets into an annular V-shaped space formed between the forward end of said cup-shaped member and the adjacent portion of said conical refractory member, a

nozzle located within said inner conical member, said nozzle being connected to a fuel supply source, and means for igniting the fuel as it is sprayed from said nozzle.

2. In blast tubes for oil burners, a tube, an inner conical member fitted in the forward portion of said tube, and a cup-shaped member fitted on the forward portion of said inner conical member and having a central aperture, a plurality of vanes forming part of said inner conical member and located in the forward portion thereof, said vanes extending inward in a longitudinally inclined plane from the inner wall of said inner conical member, said vanes having the rear portion thereof rounded and curving towards the front forming an are at a predetermined angle, thus altering the flow of air in said blast tube, a conical refractory member fitted over said cup-shaped member, and the forward portion of the latter having a plurality of holes providing outlets therefrom, the holes in said cup-shaped member being located in front of said vanes in said inner conical member, said conical refractory member tapering forward and outward from said cup-shaped member throughout the greater part of the length thereof, and the extreme forward portion of said conical refractory member tapering forward and inward from the outwardly taperir g portion thereof.

3. In blast tubes for oil burners, a tube, an inner conical member fitted in the forward portion of said tube, and a cup-shaped member fitted on the forward portion of said inner conical member and having a central aper ire, the outer surface of said inner conical member being smaller at the forward portion thereof and forming a shoulder to accommodate said cup-shaped memher, the inner wall of said inner conical member bein cylindrical at the forward portion of same and the remaining portion thereof tapering outward towards the rear, the inner wall of said cup-shaped member being cylindrical at the rear of same and forming a shoulder towards the front thereof which abuts the front edge of said inner conical member, the inner and outer surfaces of the forward portion of said cup-shaped member being of a truncated shape and tapering forward and inward, a plurality of vanes forming part of said inner conical member and located in the forward portion thereof, said vanes extending inward in a longitudinally inclined plane from the cylindrical portion of said inner conical member, said vanes having the rear portion thereof rounded and curving towards the front forming an are at a predetermined angle, thus altering the flow of air in said blast tube, the forward portion of said cup-shaped member having a plurality of-hcles extending therethrough, a conical refractory member fitted over the rear portion of said cup-shaped member and extendin forward and outward therefrom over the forward portion of said cup-shaped member, the holes in said cup-shaped member providing outlets intoan annular V-shaped space formed between the forward end of said cup-shaped member and the adjacent portion of said conical refractory member, and the extreme forward portion of said conical refractory member tapering forward and inward from the outwardly tapering portion thereof, a nozzle located within said inner conical member, said nozzle being connected to a fuel supply source, and means for igniting the fuel as it is sprayed from said nozzle.

ALBERT EDWARD WATTS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,336,261 Scott Apr. 6,1920 1,670,626 Lalor May 22, 1928 1,719,090 Stillman July 2, 1929 1,975,033 Wolff Sept. 25, 1934 2,066,651 Sherman Jan. 5, 1937 2,344,519 Nagel Mar. 21, 1944 2,347,594 De Lin Apr. 25, 1944 2,393,897 Glendenning Jan. 29, 1946 

